1. Field of the Invention
This invention relates to metering valves for pressurized dispensing containers. More particularly, the invention relates to valves for aerosol containers the contents of which are to be dispensed in a metered fashion so that only a limited amount of product is dispensed at one actuation of the valve.
2. Description of the Prior Art
The prior art, of course, is replete with illustrations of metering dispensing valves for pressurized aerosol containers. A large number of such valves involve the use of a plunger, the lower end of which is adapted to block the inlet to the valve housing when the plunger is depressed so that no further product is permitted to enter the housing and only the product already in the housing at the commencement of the actuation is dispensed.
Other prior art discloses the concept of using an object such as a metal ball, as in the case of Howell U.S. Pat. No. 2,693,983, granted Nov. 6, 1954, to close off the housing inlet during dispensing. An additional disclosure in which a resilient ball is used is in the Beard U.S. Pat. No. 2,932,432 which issued Apr. 12, 1960.
In the latter patent, embodiments are disclosed which utilize a resilient ball, and dispose the housing inlet at a position offset from the centerline of the housing. This was done presumably to assure that when the actuation was concluded and the plunger permitted to rise, the ball would not remain seated, blocking the housing inlet.
The earlier patent contemplates the closing of the inlet by having the plunger squash out the resilient ball so that its circumference engages the walls of the housing above the actual housing inlet. Apparently, the concept of seating the resilient ball on an annular seat immediately surrounding the housing inlet was not hit upon in the prior art because of the supposed difficulty in assuring that the ball would unseat once the plunger was released and permitted to travel up.